Coil support for electromagnets



G. c. ARMSTRONG ET AL con. surroa'r FOR ansc'momeus'rs June 18, 1940.

Original Filed Aug. 28, 1936' 2 Sheets-Sheet 1 INVENTOR S. 6 eorgeCflrmstrqng anfi/b er El/z 6 ifi A g WITNESSES: A XAM ,3, [Z M June 1940. e. c. ARMSTRONG ET AL 2,205,234

0011; SUPPORT FOR ELECTROMMENETS Original Fild Aug.- 28, 1936' 2 Sheets-Sheet 2 Fig.6. Fig-Z J Fig.8-

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Patented June 18, 1940 UNITED STATES PATENT OFFICE Ellis, Forest Hills, house Electric &

Pa., assignors to Westing- Manufacturing Company,

East Pittsburgh, Pa., a corporation of Pennsylvania Original application August 28, 1936, Serial No.

98,323. Divided and this application August 6, 1937, Serial No. 157,853

3 Claims.

Our invention relates to magnetically-actuated switches or contactors and it has particular relation to improvements in the design and construction of coil support structures for contactor actuating magnets of the alternatingcurrent energized type.

This application is a division of our copending application Serial No. 98,323, filed August 28, 1936, now Patent No. 2,157,844 issued May 9, 1939, for Electrical contactors, and assigned to the same assignee as this application.

Generally stated, the object of our invention is to facilitate the manufacture, improve the performance and lengthen the life of such magnets.

A more specific object is to provide a magnet which is tilt and shock proof, requires a minimum of space, has an efficient torque curve and high opening speed characteristic, and is so constructed that switches having different current capacity ratings may be constructed largely of common parts.

Another object is to facilitate an adjustment of the pull characteristics of the magnet.

A further object is to make improved provision for varying the thickness of the core-part lamination stacks.

A still further object is to provide improved supporting and spacing means for the magnet winding.

An additionalobject is to facilitate the manufacture and installation and to prolong the life of shading coils for the pole pieces of the magnet.

Our invention, together with additional objects and advantages will best be understood from the following description of a specific embodiment when taken in conjunction with the accompanying drawings, in which:

Figure 1 is a view in front elevation of a contactor utilizing a magnet which incorporates the several improvements of our invention,

Fig. 2.is a view inside elevation of the complete device of Fig. 1,

Fig. 3 is a view in side elevation of one of the sets of contacts of the contactor of Fig. 1,

Fig. 4 is a view iniront elevation of a portion of the magnet showing how the stacks of corepart laminations may be increased,

Fig. 5 is a view taken along section line V-V of Fig. 2 showing the spacing between the magnet core leg and the winding which surrounds it.

Figs. 6, 7 and 8 are views showing the design and arrangement of the brackets utilized to support the magnetwinding.

Fig. 9 is a diagram of curves showing the relation between the pull characteristics of the actuating magnet and the torquerequirements of the I contactor of Figs. 1 and 2,

Fig. 10 is a simplified representation of a magnet having a winding adapted for adjustable positioning, and

Fig. 11 is a diagram of curves showing the relation between winding position and torque charwhich supports stationary contacts II! by means of a panel member 24. The cooperating movable contacts l2 are carried by a shaft bar 26 which, through bearing pins 28, is rotatably supported between the lower ends of the frame legs.

One end of this shaft bar carries the armature or movable core portion 30 of the device-actuating magnet. The stationary core portion 32 of the magnet is attached to the side of one of the legs of frame l6 and has a downwardly extending center leg around which the magnetizing winding I4 is positioned.

In the construction illustrated, frame I6 is adapted to position the device contacts and magnet in full operative relation and to support the complete contactor from a mounting panel or v other supporting structure (not shown). This unit or self-contained form of construction is more completely described by our copending application, Serial No. 98,322, filed August 28, 1936.

The circuit to be controlled (not shown) is connected with the stationary contacts through lugs 20 and with the moving contacts through flexible shunts 22. Associated with each set of contacts ill-l2 is an arc box 23 supported by a blowout coil 25. These boxes form a part of an improved arc quenchin equipment, more completely shown and described by our copending application, Serial No. 98,324, filed August 28, 1936. In order to better show the construction and arrangement of the device contact parts, the view of Fig. 1 illustrates only one of the three boxes 23 in position.

The improved actuating magnet of our invention is of the E-core vertical-lift type. That is, the E- shaped stationary core portion 32 is mounted with the legs projecting downwardly while the cooperating armature or movable core portion III is arranged to be attracted upwardly. Aslong as the magnet winding is deenergized,

shaft bar 26 into the contact-engaging'position I thereby completing the controlled circuit. Springs 33 form a part of the connections between the bar 26 and the movable contacts i2. When in the above-referre'd-to engaging position,

the bar is advanced somewhat beyond the pointy of initial contact touching.

This further motion compresses the springs storing in them energy which during the period of device opening raises the speed of contact separation. Deenergization of .the magnet winding releases the armature 3|! and by action of gravity and the force of springs 33, it is urged downwardly causing contacts I2 to separate from members In with a rapidity and through a distance suflicient to interrupt the controlled circuit current.

In order that the contactor may be substantially shock and tilt proof, the moving parts are adapted, in the manner shown, for vertical lift. With this arrangement, the tendency of severe jars or tilts through large angles to change the position of the movable contacts I! relative to the stationary contacts I 0 is minimized.

The use of an E-type magnet mounted in the manner shown to provide a vertical lift of its with the shaft bar 26.

armature also economizes space. For the production of a given torque through a given angle. this form of magnet is decidedly superior. It has the further advantages of being compact and mechanically rugged.

The vertical lift arrangement also affords the maximum speed of contact opening. When the armature 30 is released the rotative force transmitted to shaft bar 26 by compression springs 33 is supplemented by the weight of the moving structure parts including that of armature 30. The resulting high speed of separation lowers the time of contact burning and thereby increases the contact life.

In order to elevate the rate at which the moving parts accelerate upon the release of armature 30, this armature is made as light in weight as possible. This is accomplished by reducing its mass to a minimum without sacrificing pull strength. In accomplishing this, we use high quality steel laminations and reduce to a negli gible length the outer legs 36 of the armature member. The central leg 38 is adapted to project some distance up into the magnetizing winding H, in order to strengthen the pull of the magnet.

In order to limit the downward travel of the magnet armature, a stop member 40 is provided. It engages with an extension of the bracket 42 by means of which the armature is connected to attraction between the armature and the steel stop bracket 40, a separating insert 44 of nonmagnetic material is provided. The bracket 42 may be detached from the bar 26 without releasing a cooperating bearing bracket 46.

The magnet construction illustrated has pull characteristics which eflectively coordinate with the torque requirements of the contactor. This relation is illustrated in Fig. 9, in which curve ll depicts the pulling effect of the armature an angle of contact To prevent lockout due through the entire range of its angle of travel theta. The torque requirements of the actuated contactor are depicted by the straight line curve portions therebeneath.

When the contactor is in the open position illustrated in Figs. 1, 2 and 3, gravity alone constitutes the opposition to upward movement of the parts carried by shaft bar 2'. Horizontal point 52, the contact members engage. the compression of springs 33, the force of opposition to upward movement abruptly rises. The upper end of line 52 represents the point at which it is Just overcome. Further decrease in the angle of opening additionally compresses springs 33 and requires an applied force which progressively increases along the line 54. The upper end of ghis1 line represents the fully closed position of the ev ce.

Our improved magnet enables the pick-up voltage to be substantially equal to the seal-in voltage. The pick-up requirements are designated by line 56 in Fig. 9 and the seal-in requirements by line H. The curve ll represents a pull curve that is characteristic of the armature torque throughout its angle of application of normal the illustrated characteristics permit the use of spring compression which is large allowance for contact an amply high initial consufllcient to give a wear and to provide tact pressure.

require higher tactors having smaller ratings. served that these such as is illustrated in Fig. 4.

In our improved arrangement, a thicker stationary member 32' may be mounted merely by the use of longer holding rivets and bolts 60. Similarly, the armature 30 may be increased to thickness 30' by removingfrom the side of supporting bracket 42 the spacer 62 and extending the laminations along the entire length of the supporting rivet 64. Exactly the same parts, therefore, are used in both cases. Should it be desired to narrow the laminations below the thickness shown in Fig. 1, this may be done by the use of shorter bolts "-and a wider spacer 62. Adjustment through a very wide range is, therefore, possible.

Our improved construction also contemplates another method of changing the pull characteristic of the magnet. This is accomplished by positioning the winding H at diilerent points along the length of thecentral core leg which it surrounds. The eiiect of'such positional vari-- ation is depicted by Figs. and 11.

When the winding is mounted in the uppermost position in which its lower end aligns with the lower extremity 88 of the central pole piece, the pulling eifect of the magnet is lowest, as represented by the lowest curve of Fig. 11. As the position of the winding is lowered, in the device of Fig. 10, causing the ratio of a: to d to be increased, the pull of the magnet progressively rises as indicated by the upper curves of Fig. 11.

In order to carry this. principle into practice, we prefer to utilize the form of winding support illustrated in Figs. 6 to 8, inclusive. This comprises a pair of brackets 10 which are attached to opposite sides of the tubular central member I II of the winding and the top projecting portions of which are secured to the structure of core piece 32.

Attachment of the brackets to the winding spool is preferably effected in the manner shown in Figs. 6 to 8. A projection H punched from the bracket body is passed through a cooperating opening in the wall of winding tube I2 and then bent upwardly into the position shown by the full lines in Fig. '7. The lower end of the bracket may also be flanged outwardly into contact with the lower portion of the winding structure. This provides a very firm andrugged form of support.

The upper portions of the brackets are then held in the desired position with respect to the core piece 32 by a bolt 16 or other securing means. By altering the point of attachment I8 vertically, the position of the longitudinal center of the winding may be varied axially along the length of the surrounded core leg. This permits a variation in the character of the pull in curve 48 to adapt the contactor to widely varying torque requirements- Among these requirements are changes in the gravity load and pickup torque which accompany variations in core thickness. The range of adjustment of winding position'may be further extended by substituting a slot ll (Fig. 8) for the attaching hole in the top of bracket ll.

In order to provide ventilating spaces between the winding and the surrounded core leg, we utilize the expedients shown in Fig.5. Spacing in one direction is' maintained by making the outer laminations ll wider than those which make up the body of the core leg. The heads 82 of the. rivet which holds the laminations together are projected suihciently to space the'coil interior from the core leg in the other direction.

The described combination of winding, supporting and spacing means is found especially suitable for the illustrated application in which the requirements of rigidity and durability are unusually high. It is both simple and inexpensive and may be used in situations where the surrounded core leg extends in a direction other than the vertically downward one shown.

Although we have shown and described certain specific embodiments of our invention. we

tube are .fully aware that many modifications thereof are possible. Our invention, therefore, is not tov be restricted except insofar as is necessitated by the prior art and by the scope of the appended claims.

We claim as our invention:

1. In an electromagnet comprising a core structure having a winding leg of rectangular cross-section extending therefrom and a winding surrounding said leg, the combination of n supporting means for said winding comprising a tube of insulating material having a'r'ectangular section integral with the winding and positioned about said core within said winding, and

a pair of flat bracket members positioned on opposite sides of the winding leg of the core within said tubeand attached to the tube, said bracket members being provided with projections extending therefrom through openings provided in the wall of the insulating tube and bent back against the outer surface of the tube to grip the tube for supporting the winding in fixed relation to the core.

2. In an electromagnet comprising a core structure having a winding leg of rectangular cross-section extending therefrom and a winding surrounding said leg, the combination of supporting means for said winding comprising a tube of insulating material having a rectangular section integral with the winding and positioned about said core within said winding, and a pair of flat bracket members extending on opposite sides of the winding leg of the core within said tube and attached to the tube, said bracket members being provided with projections extending therefrom through openings provided in the wall of the insulating tube and bent back against the outer surface of the tube to grip the tube, said bracket members being flanged outwardly at oneiend of the winding for supporting the winding in fixed relation to the core.

3. In an electromagnet comprising a core structure having a winding leg of rectangular cross-section extending therefrom and a. winding surrounding said leg, the combination of supporting means for said winding comprising a tube of insulating material having a rectangular section integral with the winding and positioned about said core within said winding, and a pair of flat bracket members extending on opposite sides of the winding leg of the core'within said tube and attached to the tube, said bracket members being provided with projections extending therefrom through openings provided in the wall of the insulating tube and bent back against the outer surface of the tube to grip the tube, said bracket members being flanged outwardly at one end of the winding for supporting therein for adjustably securing the winding in fixed relation to the core.

GEORGE C. ARMSTRONG. DEL-BERT mil-J5. 

